During the last two decades a great number of gas injection devices have been reported to be used in metallurgical reactors containing liquid metals. The main differences between most of them deal with design aspects such as number and distribution of gas passages; gas distribution chamber geometry and location; use or not of a metallic can surrounding the refractory element; use of porous or solid refractories; methods for assembling all the components; etc. Little attention has been paid to the practical aspect of interchange of an injection device. This aspect is of great importance because the replacement operation, if takes too much time, costs more and decreases the availability of the metallurgical reactor.
It is upon the experience of the authors of this invention, in designing and using injection devices for the treating of liquid metals in industrial metallurgical reactors, that a method has been found to overcome the main problems associated with the gas injection technology.
Two possible solutions appear to be the most effective for the interchangeability aspect: to install a long life injection element or to install an interchangeable element with a design oriented toward the solution of problems encountered during the replacement operations.
The long life characteristic in an injection device is related to the wearing produced by the "back attack" phenomenon resulting in a high wearing rate. This phenomena is increased when the refractory of the injection device is porous. The quick interchangeability of an injection device depends on the following factors: presence of a metallic "mushroom" on the hot face of the injection device; diffusion or reaction bonding between the lateral surface of the injection element and the surrounding refractory brick; and having means to apply a force in the opposite direction to the gas flow (in the injection element) and means to transmit said force at all points of the injection element in order to extract it.
It is, therefore, an object of this invention to provide an injection device to be used in metallurgical reactors with an improved design to operate for long periods withstanding operation conditions with little or no wearing.
It is another object of the present invention to provide an injection device to be used in metallurgical reactors with an improved design that may be replaced quickly.